I have purchase a York Executive X.3500 rowing machine many years ago and I need to replace the (6) seat carriage roller Part # 56001-42 ref# CP46-78375, can you please let me know the price and where I can buy these?

Parts suppliers. You might even get rollers from Bunnings.

https://www.google.com/search?q=Crane+Waterflow+Rowing+Machine+parts

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If the LED's have blown then they need replacing, if the LED's are ok then the T-con board is faulty.

Remove the bearings and take them to your local Industrial Supply retailer, they should be able to cross reference and get you the ones you need.

You need to get someone out to look at it. Noise issues are rarely able to be diagnosed remotely.

http://www.yorkfitness.com/media/downloads/rowingmachinesr700rowerinstructions.pdf

Find it here:
manualfox.com/link/weider.htm

Good News! Home Depot sells (on-line only) drawer rollers that work PERFECTLY for the Tunturi Rower machine seat rollers. The only difference is the wheels are nylon instead of rubber. Model Number R7228, Internet Number: 100142874. Item description: ROLLER, W/ 1/4" -20 STUD, 1-1/8" NYLON, BALL BEARING. There are two rollers in a package, $5 for two! http://www.homedepot.com/buy/prime-line-1-1-8-in-nylon-ball-bearing-drawer-rollers-2-pack--r-7228.html

Good News! Home Depot sells (on-line only) drawer rollers that work PERFECTLY for the Tunturi Rower machine seat rollers. The only difference is the wheels are nylon instead of rubber. Model Number R7228, Internet Number: 100142874. Item description: ROLLER, W/ 1/4" -20 STUD, 1-1/8" NYLON, BALL BEARING. There are two rollers in a package, $5 for two! http://www.homedepot.com/buy/prime-line-1-1-8-in-nylon-ball-bearing-drawer-rollers-2-pack--r-7228.html